Gastroparesis is a common condition. The upper portion of a human stomach generates electrical waves that sweep across the antrum, causing the stomach to contract, to grind food and to empty food into the intestines. Gastroparesis occurs when the rate of the electrical waves slow and the stomach muscles contract less frequently. Common symptoms of gastroparesis include nausea, vomiting, a feeling of fullness after only a few bites of food, bloating, and excessive belching.
Gastroparesis is caused by either diseases of the stomach muscles or the nerves that control these muscles. It is commonly associated with diabetes mellitus, which damages the nerves controlling the stomach muscle. Other causes include nervous reflexes, imbalance of potassium, calcium or magnesium, certain medications and certain diseases. Scars and fibrous tissue from ulcers and tumors that block the outlet of the stomach can mimic gastroparesis.
Gastroparesis is diagnosed based on symptoms and physical examination. A gastric emptying study is the most common method to measure the emptying of food from the stomach. An Upper gastrointestinal endoscopy test is another common examination to exclude the possibility of an obstruction as the cause of the patient's symptoms. An antro-duodenal motility study measures the pressure that is generated by the contractions of the stomach and intestinal muscles. Another test is an electrogastrogram (EGG), which records the electrical signals that travel through the stomach muscles and control the muscles' contractions. The electrical signals normally precede each contraction. In most patients, the rhythm of the electrical signals is either irregular or there is no post-meal increase in electrical power. Although an EGG does not measure gastric emptying directly, it is an attractive test for suspected gastroparesis.
Currently available medications treat gastroparesis by stimulating the stomach to contract more normally. Metoclopramide is an effective medication that has side effects such as restlessness, fatigue, agitation and depression. Another drug is domperidone, which has not been approved in the United States. The third drug is erythromycin, which stimulates short bursts of strong contractions that are more like the contractions that sweep undigested food into the colon than regular digestive contractions. Like erythromycin, octreotide, a hormone-like drug, can be injected underneath the skin to stimulate short bursts of strong contraction. The last resort is surgery, which is occasionally used to create a larger opening between the stomach and the small intestine in order to facilitate the process of emptying the stomach.
Gastroparesis may become worse with time. Motility disorders of the muscles of the small intestine and colon make gastroparesis difficult to treat. There remains a need for an effective treatment for gastroparesis.